1 /* 2 * FPGA Manager Driver for Lattice iCE40. 3 * 4 * Copyright (c) 2016 Joel Holdsworth 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 of the License. 9 * 10 * This driver adds support to the FPGA manager for configuring the SRAM of 11 * Lattice iCE40 FPGAs through slave SPI. 12 */ 13 14 #include <linux/fpga/fpga-mgr.h> 15 #include <linux/gpio/consumer.h> 16 #include <linux/module.h> 17 #include <linux/of_gpio.h> 18 #include <linux/spi/spi.h> 19 #include <linux/stringify.h> 20 21 #define ICE40_SPI_MAX_SPEED 25000000 /* Hz */ 22 #define ICE40_SPI_MIN_SPEED 1000000 /* Hz */ 23 24 #define ICE40_SPI_RESET_DELAY 1 /* us (>200ns) */ 25 #define ICE40_SPI_HOUSEKEEPING_DELAY 1200 /* us */ 26 27 #define ICE40_SPI_NUM_ACTIVATION_BYTES DIV_ROUND_UP(49, 8) 28 29 struct ice40_fpga_priv { 30 struct spi_device *dev; 31 struct gpio_desc *reset; 32 struct gpio_desc *cdone; 33 }; 34 35 static enum fpga_mgr_states ice40_fpga_ops_state(struct fpga_manager *mgr) 36 { 37 struct ice40_fpga_priv *priv = mgr->priv; 38 39 return gpiod_get_value(priv->cdone) ? FPGA_MGR_STATE_OPERATING : 40 FPGA_MGR_STATE_UNKNOWN; 41 } 42 43 static int ice40_fpga_ops_write_init(struct fpga_manager *mgr, 44 struct fpga_image_info *info, 45 const char *buf, size_t count) 46 { 47 struct ice40_fpga_priv *priv = mgr->priv; 48 struct spi_device *dev = priv->dev; 49 struct spi_message message; 50 struct spi_transfer assert_cs_then_reset_delay = { 51 .cs_change = 1, 52 .delay_usecs = ICE40_SPI_RESET_DELAY 53 }; 54 struct spi_transfer housekeeping_delay_then_release_cs = { 55 .delay_usecs = ICE40_SPI_HOUSEKEEPING_DELAY 56 }; 57 int ret; 58 59 if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) { 60 dev_err(&dev->dev, 61 "Partial reconfiguration is not supported\n"); 62 return -ENOTSUPP; 63 } 64 65 /* Lock the bus, assert CRESET_B and SS_B and delay >200ns */ 66 spi_bus_lock(dev->master); 67 68 gpiod_set_value(priv->reset, 1); 69 70 spi_message_init(&message); 71 spi_message_add_tail(&assert_cs_then_reset_delay, &message); 72 ret = spi_sync_locked(dev, &message); 73 74 /* Come out of reset */ 75 gpiod_set_value(priv->reset, 0); 76 77 /* Abort if the chip-select failed */ 78 if (ret) 79 goto fail; 80 81 /* Check CDONE is de-asserted i.e. the FPGA is reset */ 82 if (gpiod_get_value(priv->cdone)) { 83 dev_err(&dev->dev, "Device reset failed, CDONE is asserted\n"); 84 ret = -EIO; 85 goto fail; 86 } 87 88 /* Wait for the housekeeping to complete, and release SS_B */ 89 spi_message_init(&message); 90 spi_message_add_tail(&housekeeping_delay_then_release_cs, &message); 91 ret = spi_sync_locked(dev, &message); 92 93 fail: 94 spi_bus_unlock(dev->master); 95 96 return ret; 97 } 98 99 static int ice40_fpga_ops_write(struct fpga_manager *mgr, 100 const char *buf, size_t count) 101 { 102 struct ice40_fpga_priv *priv = mgr->priv; 103 104 return spi_write(priv->dev, buf, count); 105 } 106 107 static int ice40_fpga_ops_write_complete(struct fpga_manager *mgr, 108 struct fpga_image_info *info) 109 { 110 struct ice40_fpga_priv *priv = mgr->priv; 111 struct spi_device *dev = priv->dev; 112 const u8 padding[ICE40_SPI_NUM_ACTIVATION_BYTES] = {0}; 113 114 /* Check CDONE is asserted */ 115 if (!gpiod_get_value(priv->cdone)) { 116 dev_err(&dev->dev, 117 "CDONE was not asserted after firmware transfer\n"); 118 return -EIO; 119 } 120 121 /* Send of zero-padding to activate the firmware */ 122 return spi_write(dev, padding, sizeof(padding)); 123 } 124 125 static const struct fpga_manager_ops ice40_fpga_ops = { 126 .state = ice40_fpga_ops_state, 127 .write_init = ice40_fpga_ops_write_init, 128 .write = ice40_fpga_ops_write, 129 .write_complete = ice40_fpga_ops_write_complete, 130 }; 131 132 static int ice40_fpga_probe(struct spi_device *spi) 133 { 134 struct device *dev = &spi->dev; 135 struct ice40_fpga_priv *priv; 136 struct fpga_manager *mgr; 137 int ret; 138 139 priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); 140 if (!priv) 141 return -ENOMEM; 142 143 priv->dev = spi; 144 145 /* Check board setup data. */ 146 if (spi->max_speed_hz > ICE40_SPI_MAX_SPEED) { 147 dev_err(dev, "SPI speed is too high, maximum speed is " 148 __stringify(ICE40_SPI_MAX_SPEED) "\n"); 149 return -EINVAL; 150 } 151 152 if (spi->max_speed_hz < ICE40_SPI_MIN_SPEED) { 153 dev_err(dev, "SPI speed is too low, minimum speed is " 154 __stringify(ICE40_SPI_MIN_SPEED) "\n"); 155 return -EINVAL; 156 } 157 158 if (spi->mode & SPI_CPHA) { 159 dev_err(dev, "Bad SPI mode, CPHA not supported\n"); 160 return -EINVAL; 161 } 162 163 /* Set up the GPIOs */ 164 priv->cdone = devm_gpiod_get(dev, "cdone", GPIOD_IN); 165 if (IS_ERR(priv->cdone)) { 166 ret = PTR_ERR(priv->cdone); 167 dev_err(dev, "Failed to get CDONE GPIO: %d\n", ret); 168 return ret; 169 } 170 171 priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); 172 if (IS_ERR(priv->reset)) { 173 ret = PTR_ERR(priv->reset); 174 dev_err(dev, "Failed to get CRESET_B GPIO: %d\n", ret); 175 return ret; 176 } 177 178 mgr = devm_fpga_mgr_create(dev, "Lattice iCE40 FPGA Manager", 179 &ice40_fpga_ops, priv); 180 if (!mgr) 181 return -ENOMEM; 182 183 spi_set_drvdata(spi, mgr); 184 185 return fpga_mgr_register(mgr); 186 } 187 188 static int ice40_fpga_remove(struct spi_device *spi) 189 { 190 struct fpga_manager *mgr = spi_get_drvdata(spi); 191 192 fpga_mgr_unregister(mgr); 193 194 return 0; 195 } 196 197 static const struct of_device_id ice40_fpga_of_match[] = { 198 { .compatible = "lattice,ice40-fpga-mgr", }, 199 {}, 200 }; 201 MODULE_DEVICE_TABLE(of, ice40_fpga_of_match); 202 203 static struct spi_driver ice40_fpga_driver = { 204 .probe = ice40_fpga_probe, 205 .remove = ice40_fpga_remove, 206 .driver = { 207 .name = "ice40spi", 208 .of_match_table = of_match_ptr(ice40_fpga_of_match), 209 }, 210 }; 211 212 module_spi_driver(ice40_fpga_driver); 213 214 MODULE_AUTHOR("Joel Holdsworth <joel@airwebreathe.org.uk>"); 215 MODULE_DESCRIPTION("Lattice iCE40 FPGA Manager"); 216 MODULE_LICENSE("GPL v2"); 217